Up to the present time, gas leak detection systems have been relatively heavy and cumbersome and are normally mounted on special vans outfitted with the several hundred pounds of equipment which are normally employed. Many of the conventional systems include one or more large inverted funnels, with conduits which are frequently in the order of 2 inches in diameter leading back toward the gas detection equipment. Representative systems of this type include E. R. Lloyd, et al, U.S. Pat. No. 3,107,517, granted Oct. 22, 1963; C. A Heath, U.S. Pat. No. 3,364,727, granted Jan. 23, 1968; M. C. Kelsey, et al, U.S. Pat. No. 3,416,357, granted Dec. 17, 1968; and D. P. Hearn et al, U.S. Pat. No. 3,444,721, granted May 20, 1969. Because of the large volume of air included in the system, it is conventional in these systems to use large volume heavy duty centrifugal fans to pull the air in the funnels and the large diameter tubes. However, the gas analyzing apparatus is normally of relatively small gas handling capacity, and cannot use the entire volume of air which is drawn through the system. Accordingly, only a small sample of the gas is routed to the gas analyzer, with resultant significant decrease in the density of the gas which is being detected in parts per million. Also, the funnels through which the air is drawn are large and rigid; accordingly, they normally cannot be located close to the ground, as such a location would cause damage to these input funnels when road irregularities are encountered. Incidentally, the funnel shaped intake arrangements appear to be predicated on the concept that leaking gas, like smoke, rises. Instead, the diffusion and effect of wind are substantially greater than the tendency of the gas to rise and therefore the funnel shaped detectors located a foot or so above the ground are much less effective than may be anticipated.
A collateral disadvantage of the systems which have been used heretofore is their excessive weight. With a weight of 200 pounds or more, it is impractical to transport the equipment as carry-on luggage on a commercial airplane flight. Accordingly, the truck on which the equipment is normally mounted is restricted in its usage to handling the heavy detection gas equipment, and correspondingly the gas detection equipment may not be readily transported extended distances and quickly mounted on a rented car or other vehicle normally used for other purposes.
An important object of the present invention is to increase the sensitivity of gas leak detection apparatus.
A subordinate object of the present invention is to provide a lightweight portable gas leak detection system which may be easily hand carried and rapidly attached to a rented car, for example, for use in a city distant from the base location of the equipment.